1. Field of the Invention
The present invention relates to a supplementary therapeutic agent which is employed to improve the effects produced by an immunopotentiator. The invention also relates to a therapeutic agent for immunodeficiency syndromes, such as chronic fatigue syndrome, low NK (natural killer) syndrome, acquired immunodeficiency syndrome, or congenital immunodeficiency syndromes.
2. Discussion of the Background
Several therapeutic agents are available for the treatment of immunodeficiency syndromes such as chronic fatigue syndrome, low NK syndrome, acquired immunodeficiency syndrome or congenital immunodeficiency syndromes. These immunopotentiators include lentinan, OK-432 (a lyophilized preparation of a low virulent strain, Su of Streptococcus hemolyticus), sizofiran, etc. (New Journal of Japanese Medicine, No. 3212, Nov. 16, 1985). E.P. 0561408 A1 teaches the use of polysaccharides having .beta.-1,3-glucoside such as sizofiran, lentinan for treatment of chronic fatigue syndrome. A potentiator for host defense mechanism using lentinan is described in proceedings of the Seventh symposium on Host Defense mechanisms against cancer, Hakone, Nov. 8-10, 1985 (p. 221-p. 229). Unfortunately, in patients with such syndromes for several years, the expected therapeutic effects of these immunopotentiators are not always produced when they are administered alone.